Re: Sequence Access Method WIP

On 5 November 2014 17:32, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com> wrote:

> Why does sequence_alloc need the current value? If it's a "remote" seqam,
> the current value is kept in the remote server, and the last value that was
> given to this PostgreSQL server is irrelevant.
>
> That irks me with this API. The method for acquiring a new value isn't fully
> abstracted behind the AM interface, as sequence.c still needs to track it
> itself. That's useful for the local AM, of course, and maybe some others,
> but for others it's totally useless.

Please bear in mind what seqam is for...

At present it's only use is to provide Global Sequences. There's a few
ways of doing that, but they all look sorta similar.

The only other use we thought of was shot down, so producing the
perfect API isn't likely to help anyone. It's really not worth the
effort to produce a better API.

BDR doesn't require Global Sequences, nor are Global Sequences
restricted in their use to just BDR - lots of cluster configurations
would want something like this.

--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services